Sampling Considerations for Wastewater Surveillance of Antibiotic Resistance in Fecal Bacteria

Patricia M C Huijbers; Julián Bobis Camacho; Marion Hutinel; D G Joakim Larsson; Carl-Fredrik Flach

doi:10.3390/ijerph20054555

Sampling Considerations for Wastewater Surveillance of Antibiotic Resistance in Fecal Bacteria

Int J Environ Res Public Health. 2023 Mar 4;20(5):4555. doi: 10.3390/ijerph20054555.

Authors

Patricia M C Huijbers^{1

2}, Julián Bobis Camacho^{1

2}, Marion Hutinel^{1

2}, D G Joakim Larsson^{1

2}, Carl-Fredrik Flach^{1

2}

Affiliations

¹ Centre for Antibiotic Resistance Research in Gothenburg (CARe), University of Gothenburg, 40530 Gothenburg, Sweden.
² Institute of Biomedicine, Department of Infectious Diseases, University of Gothenburg, Guldhedsgatan 10A, 40530 Gothenburg, Sweden.

Abstract

Wastewaters can be analyzed to generate population-level data for public health surveillance, such as antibiotic resistance monitoring. To provide representative data for the contributing population, bacterial isolates collected from wastewater should originate from different individuals and not be distorted by a selection pressure in the wastewater. Here we use Escherichia coli diversity as a proxy for representativeness when comparing grab and composite sampling at a major municipal wastewater treatment plant influent and an untreated hospital effluent in Gothenburg, Sweden. All municipal samples showed high E. coli diversity irrespective of the sampling method. In contrast, a marked increase in diversity was seen for composite compared to grab samples from the hospital effluent. Virtual resampling also showed the value of collecting fewer isolates on multiple occasions rather than many isolates from a single sample. Time-kill tests where individual E. coli strains were exposed to sterile-filtered hospital wastewater showed rapid killing of antibiotic-susceptible strains and significant selection of multi-resistant strains when incubated at 20 °C, an effect which could be avoided at 4 °C. In conclusion, depending on the wastewater collection site, both sampling method and collection/storage temperature could significantly impact the representativeness of the wastewater sample.

Keywords: Escherichia coli; PhenePlateTM; composite sample; grab sample; hospital effluent; sewage; temperature; time-kill test; wastewater treatment plant influent; wastewater-based epidemiology.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Anti-Bacterial Agents / pharmacology
Bacteria
Drug Resistance, Microbial
Escherichia coli*
Humans
Wastewater*
Wastewater-Based Epidemiological Monitoring

Substances

Wastewater
Anti-Bacterial Agents

Grants and funding

This work was financially supported by the Swedish Research Council Formas (grant numbers 2018-00833 and 2021-00922) to CFF, the Centre for Antibiotic Resistance Research at the University of Gothenburg to CFF, and the Swedish state under the agreement between the Swedish Government and the county councils, the ALF agreement (grant numbers ALFGBG-717901 and ALFGBG-978722) to DGJL and CFF, respectively.